Detergent gasoline composition containing 2-amino straight-chain alkanes



United States Patent Ofifice ABSTRACT OF THE DISCLOSURE Leaded gasolinecomposition containing secondary attached straight-chain alkyl primaryamines having from about 9 to 24 carbon atoms in the alkyl group.

This invention relates to improved detergent gasoline compositions forspark ignition internal combustion engines. More particularly, theinvention concerns gasoline compositions containing new detergentadditives which substantially reduce carburetor deposits in sparkignition internal combustion engines.

In the operation of spark ignition internal combustion engines therehave been problems of rough idling and engine stalling, and carburetoradjustments and reconditioning are often necessary to providesatisfactory service. It 'is found, particularly in the case ofstop-and-go driving in metropolitan areas, that such stalling and idlingproblems are more frequent, especially in the case of multithroatcarburetors of the type employed in many present-day automobiles. It hasbeen determined that the rough idling and engine stalling are primarilydue to the accumulation of deposits in the throttle body section of thecarburetors. As the deposits build up, the amount of air for givenamount of fuel is impeded and greatly reduced, and the air-fuel mixtureis overly rich for satisfactory engine operation. Frequent adjustmentsof the carburetor are needed to overcome the effect of this depositbuildup, and finally it becomes necessary to replace the carburetor orgive it a complete overhaul.

. Various additives have been suggested for use in gasoline to cut downon the buildup of carburetor deposits. However, such additives haveusually sufiered certain disadvantages as to overall effectiveness, andthe search has continued for more suitable compositions.

It has now been found that deposits in the carburetors of spark ignitioninternal, combustion engines are substantially reduced by an improveddetergent gasoline composition comprising a major proportion of ahydrocarbon base fuel boiling in the gasoline boiling range and fromabout 00001 to 1.5% by weight of branched-chain alkyl primary aminehaving from about 9 to 24 carbon atoms in the alkyl group.

The branched-chain alkyl primary amines of the gasoline"cornpositions ofthe invention are characterized by the formula CHNH:

in which one of the branches, R is a straight-chain alkyl group of from1 to 4 carbon atoms and the other branch, R is a straight-chain alkylgroup of to 22 carbon atoms. Such amines may also be described asaminoalkanes, that is, Z-aminoalkane, 3-aminoalkane or 4-aminoalkane inwhich the alk-ane is straight-chain and contains 9 to 24 carbon atoms.

3,342,570 Patented Sept. 19, 1967 Although the branched-chain alkylprimary amine is satisfactorily employed in any amounts sufficient toimpart detergency to the gasoline composition, it is preferred that itbe present in the gasoline in amounts from about 0.0001 to 1.5% byweight. For present purposes, amounts in the range from about 0.003 toabout 0.03% by Weight are most satisfactory from the standpoint ofelfectiveness and cost.

To facilitate handling, it is customary to formulate the improveddetergent additives of this invention as concentrates. Since theadditives are unusually stable and possess good solubilitycharacteristics, these concentrates represent a particular embodiment ofthe invention. In the preparation of the concentrate, the detergentadditive is dissolved in a suitable hydrocarbon or alcohol solventboiling in the range from about 150 to 400 F., preferably an aromatichydrocarbon solvent such as benzene, toluene, xylene, or higher boilingaromatics or aromatic thinners. Aliphatic alcohols of about 3 to 8carbon atoms, such as isopropanol, isobutylcarbinol, n-butanol and thelike, as well as mutually compatible mixtures of such alcohols andhydrocarbon solvents, are also suitable for use with the detergentadditive. The amounts of detergent additive in the concentrate areordinarily at least 10% by weight, and may vary up to about 70% byweight.

In addition to the detergent additive, other fuel additives may be usedin the gasoline compositions of the invention. The deposit-reducingbenefits are obtained in combination with lead alkyl antiknock agents,such as tetramethyl lead or tetraethyl lead. Such antiknock agents areordinarily employed in amounts sufiicient to enhance the octane number,usually from about 0.5 to 4 ml./gal.

A nonvolatile light mineral lubricating oil, suchas petroleum spray oil,is also a suitable additive for the gasoline compositions of theinvention. These oils are believed to act as a carrier for disperseddeposits. They are employed in amounts from about 0 .05 to 0.5% by tohaloalkanes volume based on the final gasoline composition.

The branched-chain alkyl primary amine detergent additive is availablefrom a number of sources. For example, straight-chain olefinichydrocarbons of the desired chain length may be converted byconventional methods having halogen in the 2-, 3- or 4- positions, andthe resulting haloalkanes may then be treated with ammonia to give thecorresponding branched-chain alkyl amine. The olefins also may bereacted with concentrated: (-95%) sulfuric acid,

then reacted with hydrocyanic acid, hydrolyzed with water and treatedwith an excess of aqueous caustic to give the amine. lOlefins may bereacted with nitrogen oxide compounds, for example, nitrogen tetroxide(N 0 in ether solution to give a mixture of nitronitrites,dinitroalkanes and nitronitrates which, in the presence of base onheating, are converted to nitroalkenes, which are then hydrogenated tothe corresponding aminoalkanes. Suitable aminoalkanes in general arealso available from unsaturatedaliphatic hydrocarbons by the so-calledRitter reaction as set forth in Ritter US. Patent No. 2,573,673, issuedOctober 30, 1951.

In accordance with the present invention, a preferred.

class of branched-chain alkyl primary amines and mix tures thereof isobtained by converting cracked wax olefins to the correspondinghaloalkanes and aminoalkanes.

The cracked wax olefins contain from about 9 to 24 carbon atoms, andpreferably from about 12 to 18 carbon atoms. Mixtures of cracked Waxolefins obtained by the thermal cracking of paraflin waxes areparticularly suitable. Such mixtures and their preparation are describedin various publications, including U.S. Patent No. 2,172,- 228 onProcess for the Manufacture of Olefins. The primary amines produced fromthese olefins have the amino group attached to the branched-chain alkylat the 2-, 3- or 4- positions to provide a mixture of branchedchainalkyl groups, i.e., secondary alkyl groups.

As an illustration of a suitable method of preparing particularbranched-chain alkyl primary amines in accordance with the invention, amixture of alkyl chlorides is first prepared by hydrochlorination of thethermally cracked wax olefin mixture containing from about 15 to 20carbon atoms per molecule. This gives a mixture of secondary alkylchlorides or 2-, 3- and 4-chloroalkanes, as they are otherwise termed.One mole of the alkyl chlorides thus obtained is reacted with from about10 to 20 moles of ammonia at about 160 C. under autogenous pressure inan autoclave. Reaction time is about 10 hours. The product is washedwith caustic and then with water. The yield is 80% primary amines, 4%secondary amines, olefins and 11% unconverted alkyl chlorides. Theolefins and unconverted alkyl chlorides are removed and recycled asdesired.

. The improved gasoline compositions containing the I branched-chainalkyl primary amines in accordance with the invention provide excellentdetergent performance compared to gasoline compositions containing otheralkyl amines. Such detergent properties are determined by the generallyaccepted method of appraising the gasoline compositions in the glassthrottle body engine test, which has been especially developed toobserve and to evaluate deposits in the carburetors of typical gasolineengines.

In the Glass Throttle Body Test, a 6-cylinder Plymouth automobile engineis set up in the laboratory and is provided with a conventionalcarburetor modified by the replacement of the metal throttle bodysection by a removable glass throttle body section. This glass throttlebody is a section of glass tubing A" thick, of approximately 1% outsidediameter and about 1% long. An automatic cycler or timer, which consistsof a constantspeed electric motor and a magnetic clutch, is provided forinsuring cyclic operation of the engine with 7.5 min. idle periodsfollowed by five accelerations to 2000 r.p.m. Crankcase fumes are ventedto the'carburetor air inlet, since these fumes are now known to beresponsible for the larger portion of the deposits. The engine isstarted up, using leaded gasoline containing a conventional amount oftetraethyl lead (1.5 ml./gal.), but no surfaceactive additives of anykind. It is run for 4 hours with the blowby fumes being drawn in at theair intake. The engine is then stopped, the glass body is removed, andboth sides of it are photographed. Thereupon the dirty glass body isagain installed on the engine and run for one hour on the same leadedbase gasoline compounded with the detergent-action additive. This timethe blowby fumes are not piped to the carburetor. After the run iscompleted, the glass throttle body is again photographed, and theeffectiveness of the detergent-containing gasoline (the percentage ofcleanup of deposits) is visually estimated.

In these tests, branched-chain alkyl primary amine mixtures obtainedfrom C C cracked wax olefins as described above were evaluated in thegasoline composition at a concentration of 0.003% by weight. They werefound to give a carburetor cleanup of up to 76%, whereas a typicalstraight-chain amine, namely, oleyl amine, gave a cleanup of only 57%.

In further tests, the oxidative stability of the branchedchain alkylprimary amines of the invention was determined in comparison to similarstraight-chain l-aminoalkanes. In these tests, 0.5 g. of l-amino C Calkanes obtained from cracked wax olefins was heated on an aluminumplanchet open to the atmosphere for 24 hours at 130 C. 0.4 g. was lostby evaporation. The residue weighed 0.1 g. It was dissolved in mixedaqueous-organic solvent and titrated with acid. The residue was found tocontain no base. By way of comparison, the corresponding branched-chainalkyl primary amine gave a residue of 0.1 g. which, upon titration, wasfound to contain 0.2 mm. of base. The result of this test shows that at24 hours at C. in the presence of air there was still present 55.5% ofthe original base of the branched-chain alkyl primary amine, while, onthe other hand, the l-aminoalkane analog has been completely decomposed.

The loss of base of the detergent additives as indicated above wasfurther studied. The additives were blended into white oil and heated at230 F. and at 300 F. The oil was inhibited with 4,4-methylenebis-(2,6-dit-butylphenol) against oxidation. It was found that after 24hours at 230 F., the branched-chain alkyl primary amines obtained from CC cracked wax olefins lost only about 13% of the basic nitrogen, whereasthe l-aminoalkane analogs and oleyl amine lost about 30% of the basicnitrogen under the same conditions. At 300 F., the decomposition occursat a much faster rate, and in 8 hours about 40% of oleyl amine isdecomposed while only about 8% of the branched-chain alkyl primary aminedecomposed by a loss of basic nitrogen.

In the foregoing illustrations of the invention, the effectiveness ofamines derived from mixtures of olefins, such as thermally cracked waxolefin fractions, is particularly apparent. The typical C -C olefinswhich were employed have the following weight composition:

Percent n 0-6 C 11.2 C 19.3 17 18.5 C 18.4 C 17.3 C 14.0 C 0.7

Such a mixture contains about 92% by weight of straightchain wolefins,3% a,w-diOl6finS, 3% internal olefins and 2% branched-chain, naphthenicand other hydrocarbons. In the hydrohalogenation of these olefins acatalyst, such as ferric chloride, is conveniently employed to directthe addition such that the halogen atom attaches to nonterminal carbonatoms, thereby providing the branchedchain alkyl structure for the aminefinal product. The hydrohalogenation is also customarily carried out attemperatures, such as 30 to 40 C., which are not high enough to causerearrangement of the olefin double bond. The 2-, 3- and 4-haloalkanesthus obtained are readily converted to amines by conventional proceduresas previously indicated. 1

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that numerous modifications and variations of theillustrative examples may be made in the practice of the inventionwithin the scope of the following claims.

I claim:

1. An improved detergent gasoline composition comprising a majorproportion of a hydrocarbon base fuel boiling in the gasoline boilingrange, lead alkyl antiknock agent in amount suflicient to enhance theoctane number and froma about 0.0001 to 1.5 percent by weight ofbranched-chain alkyl primary amine having from about 9 to 24 carbonatoms in the alkyl group of the formula:

in which one of the branches, R is a straight-chain alkyl group of from1 to 3 carbon atoms and the other branch,

3,342,570 5 6 2. The composition of claim 1 in which the branchedto 75percent by weight of the branched-chain alkyl prichain alkyl group ofthe structural formula denoted by: mary amine of the gasolinecomposition of claim 1.

RI References Cited 5 UNITED STATES PATENTS 1,787,789 1/1931 Lovell etal. 44-72 1,954,939 4/1934 Magness 44-80 is derived from thermallycracked wax olefin mixtures 2,684,292 7/1954 Caron et a1 44*72X havingabout 15 to 20 carbon atoms per molecule.

3. An improved detergent gasoline concentrate conm DANIEL WYMAN PrimaryExaminer sisting essentially of a hydrocarbon solvent and from 10 Y- H-SMITH, s stant Ex miner.

1. AN IMPROVED DETERGENT GASOLINE COMPOSITION COMPRISING A MAJORPROPORTION OF A HYDROCARBON BASE FUEL BOILING IN THE GASOLINE BOILINGRANGE, LEAD ALKYL ANTIKNOCK AGENT IN AMOUNT SUFFICIENT TO ENHANCE THEOCTANE NUMBER AND FROM ABOUT 0.0001 TO 1.5 PERCENT BY WEIGHT OFBRANCHED-CHAIN ALKYL PRIMARY AMINE HAVING FROM ABOUT 9 TO 24 CARBONATOMS IN THE ALKYL GROUP OF THE FORMULA: